Sewing machine needle

ABSTRACT

An improved sewing machine needle for use in sewing synthetic fabrics to prevent skipping of stitches. The needle is constructed to reduce the friction between the thread and the fabric and to influence the formation of a greater than conventional loop size which can be easily hooked by the beak of the shuttle.

United States Patent 11 1,

1451 Jan. 28, 1975 Kuromegawa [54] SEWING MACHINE NEEDLE 357,805 2/1887 Willcox 112/222 568,946 10/1896 Hanna 112/222 [75] inventor: Toru Kuromegawa, Osaka. Japan 990.4) 4/19 was 112/222 X 73 Assigneez Maruzen Sewing Machine Co" L d 3,581,688 6/1971 Kettcrcr 1 12/224 Osaka. Japan Ir'imury Examiner-Richard J. Scanlan, Jr. [22) F'led: 1973 Allurm'y, Agent, or Firm-Arnstcin, Gluck, [211 App]. N0.: 424,044 Wcitzenfeld & Minow 1521 u.s. c1. 112/222 [57] ABSTRACT [51] Int. Cl 1105b 85/00 An improved ewing machine needle for use in sewing [58] Field of Search 112/222. 224; 128/335; synthetic fabrics to prevent skipping of stitches. The 223/102 necdie is constructed to reduce the friction between the thread and the fabric and to influence the forma- [56] References Cited tion of a greater than conventionai loop size which UNITED STATES PATENTS can be easily hooked by the beak of the-shuttle.

Packard 112/222 .ill

1 Claim, 8 Drawing Figures 1 SEWING MACHINE NEEDLE BACKGROUND OF THE INVENTION This invention relates to improvements in sewing machine needles.

The sewing of modern synthetic, soft and flexible fabrics, such as polyester knits and the like on zig-zag machines has been attended with problems, in particular, the skipping of stitches during normal operation of the sewing machine. It is belived that this condition is due to a combination of factors, one of which is the relatively large area of the needle holes normally provided in the needle plate and the presser foot to accommodate the lateral zig-zag movement of the needle. In its downward travel the needle penetrates the fabric and the friction between the needle and the fabric forces that portion of the fabric disposed over the needle hole downwardly into the hole of the needle plate. In the upward travel of the needle the fabric is drawn into the needle hole of the presser foot. Thus, the fabric is.

caused to flex in the zone of the needle holes. Accordingly, the fabric is caused to move upwardly with the needle instead of lying flat and permitting the needle to move relative to the fabric. As a result, the thread passing through the fabric does not form a proper loop for engagement by the shuttle beak. The consequence is a skipped stitch.

The problem in a large measure has been remedied by the use of a novel presser foot as disclosed in application Ser. No. 248,216 filed Apr. 27, 1972. This presser foot prevents the upward movement of the fabric into the needle hole of the presser foot as the needle is caused to move upwardly. The use of the needle of the present invention complements the use of the above presser foot in that it tends to reduce the friction between the thread and the fabric while effecting the formation of a larger than conventional thread loop for engagement with the shuttle beak.

SUMMARY OF THE INVENTION One of the objects of this invention is the provision of an improved needle for use on a zig-zag sewing machine for preventing the skipping of stitches in the sewing of certain types of textile fabrics.

Another object of this invention is the provision of a needle for use in a zig-zag sewing machine which tends to reduce the friction between the thread and the fabric so as to prevent the fabric being raised with the upward travel of the needle while effecting the formation of a larger than conventional thread loop for engagement with the shuttle beak to insure against the skipping of stitches in a sewing operation.

Still a further object of this invention is the provision of a sewing machine needle which functions to bring the thread loop into closer proximity to the shuttle beak for more effective engagement of the loop by the beak.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of a sewing machine needle in accordance with my invention.

FIG. 2 is a bottom plan view thereof.

FIG. 3 is a longitudinal cross-sectional view taken substantially on line 3-3 of FIG. 1.

FIG. 4 is a cross-sectional view taken substantially on line 4-4 of FIG. 1.

FIGS. 5 and 5a are fragmentary cross-sectional views on an enlarged scale, through the lower part of the needle of my invention showing the relationship of the thread to the needle in different operative positions of the needle.

FIGS. 6 and 6a are views, similar to FIGS. 5 and 5a, showing a conventional needle and the corresponding relationship of thread to needle in similar operating positions.

BRIEF DESCRIPTION OF A PREFERRED EMBODIMENT The needle 10 of the present invention comprises a shank or body II, a head I2 and a tip I3. The head 12 is conventional being generally cylindrical with a flat surface 14 and adapted to be inserted in the needle bar of the sewing machine. A channel groove 16 extends longitudinally from the head 12 along the shank ll, communicates with the eye 17, and terminates just short of the tip 13, as illustrated in FIG. 1. The groove 16 has an average depth greater than that of conventional needles. For example, the depth of the groove 16 in a No. 14 needle, in accordance with the present invention, is approximately 0.20 millimeters greater than that of a conventional needle. Th;us, as will be apparent from FIG. 5 the thread portion 20a extending along the shank 11 is substantially'wholly contained within the groove 16 and is isolated from the fabric, thereby eliminating any friction between the thread portion 20a and the fabric. The lower terminal portion of the groove 16 tapers as at 18, substantially as shown in FIGS. 3 and 5.

l The surface of the needle diametrically opposite the groove 16 is provided with spaced upper and lower reend ramp portions 23 and 24. The ramp portion 24 terminates just short of the eye 17 which results in an enlarged portion 26 immediately adjacent the eye 17. This portion 26 has a depth which is substantially greater than any portion of the needle along the shank.

In the conventional needle 10a, illustrated in FIGS. 6 and 6a, the corresponding portion 26a immmediately adjacent the eye 17a actually has a reduced thickness in relation to the shank lla. It will also be noted that the recess 22a in the conventional needle actually is in the form of a channel groove while in the present invention the recess 22 is a low spot on the surface of the needle shank and extends fully across the width of the shank. Accordingly, the thickness of the shank 11 in the zone of the recess 22 is substantially less than the corresponding dimension in the conventional needle 10a.

The effect of the enlarged portion 26 on the thread 20 is illustrated in FIG. 5a. It will be seen that as the needle 10 begins its upward movement, after having penetrated the fabric, the enlarged portion 26 influences the formation of a loop or bight L which is larger than a loop L, formed by a conventional needle 100, the latter being illustrated in FIG. 60. That, together with the increased clearance provided by the recess 22 of the shank affords an optimum condition for hooking of the thread 20 by the shuttle beak, not shown, which substantially insures against skipping of stitches in a sewing operation.

The upper recess 21 is spaced from the lower recess 22 and, preferably, is arcuately formed in a longitudinal direction. Said recess 21 accommodates a portion of the thread on the side of the needle above the loop L and this has the effect of reducing friction between the thread and the fabric.

The tip 13 of the needle has a rounded or snub nose instead of a sharp piercing point 13a as in the conventional needle shown in FIGS. 6 and 6a. The snub nose functions to push aside the threads of the fabric as the needle penetrates the fabric instead of cutting through the threads as in the case of conventional needles.

It will be apparent from the foregoing that the needle of my invention, in operation, effects optimum sewing conditions by reducing the friction between the needle and sewing thread and the fabric being stitched so as to facilitate passage of the needle through the fabric with a minimum disturbance of the fabric, while at the same time influencing the formation of a larger than normal thread loop or bight to-be hooked by the shuttle beak, thereby insuring the formation of proper stitches in a sewing operationl Various changes coming within the spirit of my invention may suggest themselves to those skilled in the art; hence, I do not wish to be limited to the specific embodiments shown and described or uses mentioned,

but intend the same to be merely exemplary, the scope of my invention being limited only by the appended claims.

I claim:

1. A needle for a sewing macine having an oscillating shuttle having a beak which is adapted to traverse the needle, said needle comprising a head, a reduced shank integral with said head and terminating in a tip. said shank being pierced by a transverse eye spaced from said tip, said shank having on one side a longitudinal groove of substantially uniform depth extending from said head and terminating in said eye. said shank having diametrically opposite said groove a first recess located in the zone of traverse of said beak and terminating at one end in a ramp portion adjacent said eye, said shank having diametrically opposite said groove a second recess spaced from said first recess and disposed intermediate said first recess and said head, the longitudinal cross sectional area of a portion of the shank immediately adjacent and between said eye and said ramp being substantially greater than the cross sectional area of the shank in the zone of said first recess and constituting an enlargement which influences the thread 

1. A needle for a sewing macine having an oscillating shuttle having a beak which is adapted to traverse the needle, said needle comprising a head, a reduced shank integral with said head and terminating in a tip, said shank being pierced by a transverse eye spaced from said tip, said shank having on one side a longitudinal groove of substantially uniform depth extending from said head and terminating in said eye, said shank having diametrically opposite said groove a first recess located in the zone of traverse of said beak and terminating at one end in a ramp portion adjacent said eye, said shank having diametrically opposite said groove a second recess spaced from said first recess and disposed intermediate said first recess and said head, the longitudinal cross sectional area of a portion of the shank immediately adjacent and between said eye and said ramp being substantially greater than the cross sectional area of the shank in the zone of said first recess and constituting an enlargement which influences the thread passing through the eye to form a loop of substantial size so as to be easily engaged by said shuttle beak. 